The 25-year-old, who joined Villa in a £12million move from Middlesbrough during the summer, has targeted a November return.
Downing has been out of action since suffering an fractured foot in a tackle with current team-mate Stiliyan Petrov, while the winger was at Boro.
“Stewart has had the operation,” Villa boss Martin O’Neill said. “The specialist is particularly pleased with him, which is great news.
“It is just a matter now of that wound healing and Stewart taking his time.
“I hear he is targeting November. Knowing Stewart, I am surprised he didn’t say tomorrow. I think our doctor would be a bit more careful.
“He is now going to have a couple of days off but he is very buoyant indeed.”